With advance of technology, nowadays filaments and fibers may be made from many different sources. Different types of yarns are being developed to give people more comfortable clothing. These days, animal furs, nylon fibers and the like are widely used in clothing fabrics. Yarns made from plant fibers also are used to make fabrics through circular knitting machines. These fabrics also are widely used to make clothes for people. Knitting of fabrics through the circular knitting machines usually requires a yarn feeder to aid yarns to be moved to a yarn hook position so that knitting needles can pick up the yarns and form loops in the knitting process. However, the yarns are often attached with floss or prone to breaking. A poorly designed yarn feeder tends to accumulate the floss or produce broken yarns. This results in lower quality of the fabrics. Or yarn threading has to be done repeatedly and results in lower production speed.
To remedy the aforesaid problems, R.O.C. patent publication No. 394272 entitled “Improved yarn feeder for knitting machines” proposes a yarn feeder which has an inclined guiding groove below a hole of the yarn feeding portion at a lower side. The hole and the guiding groove form a juncture which has a yarn guiding aperture to enable yarns to be disposed on correct positions. And two neighboring yarns are spaced from each other at a desired distance. Hence yarn feeding is smoother and yarn breaking can be reduced. But as the yarns are passing through the yarn feeder at a high speed, the yarns traveling through the inclined guiding groove incur friction due to contact and generate a high temperature. This, plus the inclined angle of the guiding groove, is prone to break the yarns. R.O.C. patent publication No. 529639 entitled “Improved yarn feeder for knitting machines” discloses a technique to overcome the problem of broken yarns mentioned above. It has a screw hole on an upper side of a yarn feeding portion of the yarn feeder to allow a bolt to fasten an auxiliary member to the yarn feeder in an inclined manner. The auxiliary member has a narrow trough on an upper portion and a yarn feeding hole on the bottom. By adjusting the fastening position of the bolt relative to the narrow trough, the angle and distance of the yarn feeding hole may be adjusted corresponding to the knitting requirements of different yarns and knitting needles. Thereby knitting operation of the yarns is steadier and smoother. The main features are the yarn feeding hole on the yarn feeder and the adjustable auxiliary member. But adjustment is difficult. And the auxiliary member is moved upwards relative to the knitting needles. As a result, the angle between the yarns is smaller. Interference frequently occurs. This generates static charge resulting from friction incurred by high speed movement between the yarn feeder and knitting needles. If the auxiliary member is moved lower relative to the knitting needle to increase the distance between the yarns, the interval of the yarn feeders has to be increased as more than one yarn feeder and knitting needle are located on the circular knitting machine. This will increase the fabrication cost. Moreover, the yarn feeding hole has a sharp edge relative to the yarn. It tends to cut off the yarn. The friction between the yarn and the hole edge also tends to accumulate floss. This will make passing of the yarn difficult when the floss is accumulated to a certain degree, and result in yarn fracturing or knitting the floss in the fabric. The finished fabric would have bumps and result in a lower fabric quality.
To remedy the aforesaid shortcomings, R.O.C. patent publication No. 491300 entitled “Improved yarn feeder for circular knitting machines” granted to the Applicant aims to eliminate floss accumulation on the yarn. It includes a jutting yarn guiding portion on another end of a yarn feeder that is formed with a smooth and curved surface. The yarn can smoothly pass through the yarn guiding portion to enter the yarn hook of the knitting needle. The yarn guiding portion is exposed, thus the floss accumulated on the yarn guiding portion can be removed easily. Moreover, the yarn feeding portion of the yarn feeder has two yarn threading holes to thread yarns. No much additional space is needed. However, the yarns are still spaced from each other at a short distance. Static charge occurs during high speed movement of the yarn. And interference takes place between the yarns during high speed movement. The yarns could even entangle with each other and result in not smooth yarn feeding operation. In short, the conventional yarn feeders previously discussed mainly have two problems: First, yarn breaking. It is mainly caused by floss accumulation, the angle of the yarn passing through the threading hole, and the friction between the yarn and the yarn feeder. Floss accumulation is caused by the characteristics of the yarn and not avoidable. However, altering the angle of the yarn passing through the yarn threading hole can reduce yarn breaking. On the other hand, while the friction cannot be totally eliminated, the friction between the yarn and the yarn feeder still can be reduced through a suitable means. Second, the problem of the interference between the yarns. This is caused by static charge resulting from friction occurred to the yarns of a too short interval moving at high speed. The yarns tend to attach to one another and result in not smooth moving. Hence increasing the interval of the yarns is a solution to overcome this problem.